On Sat, 2005-06-04 at 09:13 -0400, Lamar Owen wrote:

Also, you would be better off using readcd instead of dd; dd is fairly dumb about error handling, but readcd knows how to deal with it.

Ditto. One thing non-Linux users also didn't know is that the way "dd" works on Linux is pretty much Linux-only (not sure about BSD).

I.e., a "true" dd of a CD/DVD media would yank in _all bits. On Linux, when you run a dd on a CD/DVD media, it looks for the first ISO9660 Yellow Book (data) track and yanks that, and not the entire disc.

What we call an ISO9660 (.iso) image is really a single track in ISO9660 Yellow Book format when it goes on the CD. While Linux hides this fact, when you dd on many other platforms, you're going to get _additional_ bits before and after. ;->

Thanks to all who answered--I learned a lot. The solution turned out to be very simple: use DVD-R media. Thanks to Bryan's explanation, I now have somewhat of an idea why.

-mj-

Bryan J. Smith wrote:

Oh man, where should I begin? I'm going to top-post, because there's just a lot of things to know. I really need to make a HOWTO (as people on the DVDRTools have been asking).

I could really "go in deep" on all the record/rewrite formats, because they are pretty different. For right now, let's assume you are using DVD-R.

In a nutshell, there are 3 major types of drive firmwares:

• Matsushita (DVD Consortium)
• Pioneer (DVD Consortium)
• Sony/Philips (DVD+RW Consortium)

Even though there are dual-format and even multi-format burners these days, there are different types of firmware supported by different types of drives.

Pioneer firmware pretty much works with any of the following "linear, character-by-character record" programs:

1. cdrecord-ProDVD (Jorg's official DVD recording program, non-GPL)
2. dvdrecord (a fork of an earlier CDRecord release, GPL)
3. cdrecord+DVDpatch (CDRecord 2.0 + DVD drive support strings)

Matsushita drives are a little different, typically only work with #1, maybe #3. #3 typically comes with most newer distros (much to Jorg's dislike, because the package is still called "cdrecord").

Most other DVD Consortium drives seem to be either Matsushita or Pioneer firmware-based, some are actually both. E.g., the LG GSA-4000 series actually support both, and _all_ DVD formats (DVD-RAM/R/RW+R+RW).

Sony/Philips firmware is a bit different, designed around the features (and limitations) non-DVD Consortium DVD+RW format. So while newer drives support dual-format, they don't support all the modes. It seems only Jorg's cdrecord-proDVD is capable of driving them.

*BUT* you don't have to use a "linear, character-by-character record" program. Yes, the most "consumer compatible" way to record a DVD-R is to do so in "disc-at-once" (DAO) mode so the laser is never turned off from beginning to end (it's also mutually exclusive with burn-proof), which is something that Sony/Philips firmware don't support (at least not until more recently).

Hence why the "dvd+rwtools" tools were created. In a nutshell they allow direct block access to the disc, instead of using a linear record. The reasons for this have to do with the fact that DVD+RW (which DVD+R is based on) drives weren't designed single-groove recording like DVD-R drives (note, DVD-RW works completely different than DVD-R), because there are inherit limitations and disadvantages with "linear, character- by-character record" (the only real positive if legacy consumer player compatibility).

So if you're recording DVD+R on a Sony/Philips drive, you want to use "dvd+rwtools." If you're recording DVD-R on a Pioneer/Matsushita drive, you want to use either cdrecord-ProDVD or cdrecord+DVDpatch. If you're swapping the two (DVD-R on S/P, DVD+R on P/M), they you might be able to use newer versions of the programs and it will work, it depends.

There's a lot of history in the formats, and the drives were designed from different viewpoints.

Pioneer, clearly for consumer player compatibility (DVD-R, DVD-RW more of an "afterthought" and not very well designed). Matsushita, clearly as an optical data archiving drive (DVD-RAM is the ultimate in reliability and longevity, but very, very slow and not consumer player compatible). Sony/Philips, clearly a high-performance MO drive, and attempted to beat Pioneer to market on a lot of things (but never did prior to dual-layer).

-- Bryan

More info (not to enough depth, hence why I need to put out a HOWTO) ...

CD-R and DVD-R are single-groove, like a vinyl record and -ROM media. The laser runs down a single, linear track, beginning to end -- a revolution actually move the head outwards.

CD-RW, DVD-RAM, DVD-RW and DVD+RW are a MO discs, with sectors, cylinders, etc... When it does a single revolution, it comes back to the same place it started, so it must "step up" to the next cylinder to emulate the same. That's why CD-RW, DVD-RAM, DVD-RW and DVD+RW are not as "compatible" with players, which expect a "single groove."

The difference with MO it's also why you should use character-by- character "record" for the "single-groove" media and a "rewrite" approach, and not MO (either the kernel packet driver -- e.g., DVD-RAM -- or dvd+rwtools -- e.g., DVD+RW/+R) for the block MO media.

MO also has a horrendous error rate, about 10^9 (1 per 1GB!). The only standard MO format (there are plenty of non-standard ones) that tries to improve that is DVD-RAM. It uses a verify after write and a media that can be re-written 100,000 times, instead of only about 1,000. But DVD- RAM is not very player compatible at all -- only a few Panasonic and Toshiba devices.

So for both longevity as well as consumer player compatibility, avoid anything MO-based.

Long story short on DVD+R, Sony/Philips originally couldn't get DVD-R to work on its drives, because of the design of its firmware and laser. They promised a new record format in DVD+R. Unfortunately, they even ran into issues, and didn't get it out until the 3rd generation of DVD +RW (2nd generation in the US -- the original 3GB DVD-R+W was Japan- only), which also led to a lawsuit against HP and others (as their DVD100i drives were marketed to support DVD+R).

I'm sure Sony/Philips wish they could turn back the clock as their promised endeavors to beat Matsushita/Panasonic to market have pretty much been the opposite (sands dual-layer, something Sony/Philips did beat them to), but what is done is done.

In the end, DVD+R is really an pie-slice MO bastard, and not a single- groove like DVD-R. Adding the lack of a DAO mode, at least in older drives, and DVD-R is the more compatible format. Unfortunately the Sony/Philips firmware was never designed for DVD-R and DAO, so you'll typically have issues with record programs for it -- which requires you to use dvd+rwtools. I highly recommend you _avoid_ DVD+R (I know people are going to differ with me on this).

Now Sony _was_ the first company to introduce a dual-format drive. And they seem to have improved the firmware as of late 2003-2004 (just about the same time as Sony/Philips finally got DVD+RW/+R interoperability improved between licensees as well as their own consumer players!), and Jorg's cdrecord-ProDVD can drive many Sony/Philips drives now. But DVD +RW was really designed for data usage, not consumer players, hence why it took awhile (despite what Sony/Philips ads say about the "most compatible consumer format").

There's been a lot of shots fired on the DVD Consortium v. DVD+RW Consortium front. I try to avoid it. I've been using DVD-RAM since '98, and adopted DVD-R in 2000 on-ward. Sony/Philips promised a lot, but they let a lot of consumers down on anything except the fact that DVD+RW is the fastest. Of course, I could get into the whole CAV v. CLV issue, which isn't really much of an issue on a "single groove" CD- R/DVD-R (because the timing and pits are always the same, linear relativity), but wreaks havoc with compatibility in a MO format (because it's in a pie-slice like arrangement, which will vary in spacing, etc...).

[ E.g., I retroactively call CAV CD-RW formats as CD+RW, because they are very, very different and can even cause "damage" to drives than CLV CD-RW. Same deal, DVD-RAM and DVD-RW are CLV, DVD+RW are CAV. There are physical format differences between a CLV MO and a CAV MO. ]

On Sat, 2005-06-04 at 02:08 -0700, Mark Jarvis wrote:

...

I have an NEC DVD-RW ND2500A (that's not the label I bought it under, but that's what it really is.) It's supposed to read/write CDs, DVDs, DVD+Rs, and DVD-Rs. I'm basically dual booting between XP and CentOS 4. Following the recipe in "The Linux Cookbook", I tried to copy a DVD using: dd if=/dev/hdd of=/tmp/diskfile.iso then cdrecord dev=/dev/hdd fs=32m -sao -v -eject -dummy /tmp/diskfile.iso to test and cdrecord dev=/dev/hdd fs=32m -sao -v -eject /tmp/diskfile.iso to actually record. I had a lot of trouble getting a good read of the whole original DVD--it kept getting an I/O error at 94-95% of the way through. After multiple cleanings and 20-40 attempts, I finally got the whole thing copied with no reported errors. It then took me a couple of tries to get the cdrecord options right and to run as root to get the requisite priority. The "-dummy" run ran with no errors that I noticed--there was an LOT of output--and "-dummy" didn't work. It wrote to the blank DVD anyway. I then did a run without the "-dummy". Although the original will play on both my PC and the DVD player hooked to the TV, the two copied DVDs (DVD+Rs) are coasters. DURN! Any solutions, suggestions, pointers to articles I should read, etc. will be appreciated. BTW, I've never quite gotten around to playing DVDs or my music files (mp3 and Real Player .rmj files) from Linux. I'd appreciate being pointed in the direction to start.